apply.con commit Increase the number of possible heads requested from git-upload-pack (319aae2)
   1/*
   2 * apply.c
   3 *
   4 * Copyright (C) Linus Torvalds, 2005
   5 *
   6 * This applies patches on top of some (arbitrary) version of the SCM.
   7 *
   8 * NOTE! It does all its work in the index file, and only cares about
   9 * the files in the working directory if you tell it to "merge" the
  10 * patch apply.
  11 *
  12 * Even when merging it always takes the source from the index, and
  13 * uses the working tree as a "branch" for a 3-way merge.
  14 */
  15#include <ctype.h>
  16
  17#include "cache.h"
  18
  19// We default to the merge behaviour, since that's what most people would
  20// expect.
  21//
  22//  --check turns on checking that the working tree matches the
  23//    files that are being modified, but doesn't apply the patch
  24//  --stat does just a diffstat, and doesn't actually apply
  25//  --show-files shows the directory changes
  26//
  27static int merge_patch = 1;
  28static int check_index = 0;
  29static int write_index = 0;
  30static int diffstat = 0;
  31static int summary = 0;
  32static int check = 0;
  33static int apply = 1;
  34static int show_files = 0;
  35static const char apply_usage[] = "git-apply [--stat] [--summary] [--check] [--show-files] <patch>";
  36
  37/*
  38 * For "diff-stat" like behaviour, we keep track of the biggest change
  39 * we've seen, and the longest filename. That allows us to do simple
  40 * scaling.
  41 */
  42static int max_change, max_len;
  43
  44/*
  45 * Various "current state", notably line numbers and what
  46 * file (and how) we're patching right now.. The "is_xxxx"
  47 * things are flags, where -1 means "don't know yet".
  48 */
  49static int linenr = 1;
  50
  51struct fragment {
  52        unsigned long oldpos, oldlines;
  53        unsigned long newpos, newlines;
  54        const char *patch;
  55        int size;
  56        struct fragment *next;
  57};
  58
  59struct patch {
  60        char *new_name, *old_name, *def_name;
  61        unsigned int old_mode, new_mode;
  62        int is_rename, is_copy, is_new, is_delete;
  63        int lines_added, lines_deleted;
  64        int score;
  65        struct fragment *fragments;
  66        char *result;
  67        unsigned long resultsize;
  68        struct patch *next;
  69};
  70
  71#define CHUNKSIZE (8192)
  72#define SLOP (16)
  73
  74static void *read_patch_file(int fd, unsigned long *sizep)
  75{
  76        unsigned long size = 0, alloc = CHUNKSIZE;
  77        void *buffer = xmalloc(alloc);
  78
  79        for (;;) {
  80                int nr = alloc - size;
  81                if (nr < 1024) {
  82                        alloc += CHUNKSIZE;
  83                        buffer = xrealloc(buffer, alloc);
  84                        nr = alloc - size;
  85                }
  86                nr = read(fd, buffer + size, nr);
  87                if (!nr)
  88                        break;
  89                if (nr < 0) {
  90                        if (errno == EAGAIN)
  91                                continue;
  92                        die("git-apply: read returned %s", strerror(errno));
  93                }
  94                size += nr;
  95        }
  96        *sizep = size;
  97
  98        /*
  99         * Make sure that we have some slop in the buffer
 100         * so that we can do speculative "memcmp" etc, and
 101         * see to it that it is NUL-filled.
 102         */
 103        if (alloc < size + SLOP)
 104                buffer = xrealloc(buffer, size + SLOP);
 105        memset(buffer + size, 0, SLOP);
 106        return buffer;
 107}
 108
 109static unsigned long linelen(const char *buffer, unsigned long size)
 110{
 111        unsigned long len = 0;
 112        while (size--) {
 113                len++;
 114                if (*buffer++ == '\n')
 115                        break;
 116        }
 117        return len;
 118}
 119
 120static int is_dev_null(const char *str)
 121{
 122        return !memcmp("/dev/null", str, 9) && isspace(str[9]);
 123}
 124
 125#define TERM_SPACE      1
 126#define TERM_TAB        2
 127
 128static int name_terminate(const char *name, int namelen, int c, int terminate)
 129{
 130        if (c == ' ' && !(terminate & TERM_SPACE))
 131                return 0;
 132        if (c == '\t' && !(terminate & TERM_TAB))
 133                return 0;
 134
 135        return 1;
 136}
 137
 138static char * find_name(const char *line, char *def, int p_value, int terminate)
 139{
 140        int len;
 141        const char *start = line;
 142        char *name;
 143
 144        for (;;) {
 145                char c = *line;
 146
 147                if (isspace(c)) {
 148                        if (c == '\n')
 149                                break;
 150                        if (name_terminate(start, line-start, c, terminate))
 151                                break;
 152                }
 153                line++;
 154                if (c == '/' && !--p_value)
 155                        start = line;
 156        }
 157        if (!start)
 158                return def;
 159        len = line - start;
 160        if (!len)
 161                return def;
 162
 163        /*
 164         * Generally we prefer the shorter name, especially
 165         * if the other one is just a variation of that with
 166         * something else tacked on to the end (ie "file.orig"
 167         * or "file~").
 168         */
 169        if (def) {
 170                int deflen = strlen(def);
 171                if (deflen < len && !strncmp(start, def, deflen))
 172                        return def;
 173        }
 174
 175        name = xmalloc(len + 1);
 176        memcpy(name, start, len);
 177        name[len] = 0;
 178        free(def);
 179        return name;
 180}
 181
 182/*
 183 * Get the name etc info from the --/+++ lines of a traditional patch header
 184 *
 185 * NOTE! This hardcodes "-p1" behaviour in filename detection.
 186 *
 187 * FIXME! The end-of-filename heuristics are kind of screwy. For existing
 188 * files, we can happily check the index for a match, but for creating a
 189 * new file we should try to match whatever "patch" does. I have no idea.
 190 */
 191static void parse_traditional_patch(const char *first, const char *second, struct patch *patch)
 192{
 193        int p_value = 1;
 194        char *name;
 195
 196        first += 4;     // skip "--- "
 197        second += 4;    // skip "+++ "
 198        if (is_dev_null(first)) {
 199                patch->is_new = 1;
 200                patch->is_delete = 0;
 201                name = find_name(second, NULL, p_value, TERM_SPACE | TERM_TAB);
 202                patch->new_name = name;
 203        } else if (is_dev_null(second)) {
 204                patch->is_new = 0;
 205                patch->is_delete = 1;
 206                name = find_name(first, NULL, p_value, TERM_SPACE | TERM_TAB);
 207                patch->old_name = name;
 208        } else {
 209                name = find_name(first, NULL, p_value, TERM_SPACE | TERM_TAB);
 210                name = find_name(second, name, p_value, TERM_SPACE | TERM_TAB);
 211                patch->old_name = patch->new_name = name;
 212        }
 213        if (!name)
 214                die("unable to find filename in patch at line %d", linenr);
 215}
 216
 217static int gitdiff_hdrend(const char *line, struct patch *patch)
 218{
 219        return -1;
 220}
 221
 222/*
 223 * We're anal about diff header consistency, to make
 224 * sure that we don't end up having strange ambiguous
 225 * patches floating around.
 226 *
 227 * As a result, gitdiff_{old|new}name() will check
 228 * their names against any previous information, just
 229 * to make sure..
 230 */
 231static char *gitdiff_verify_name(const char *line, int isnull, char *orig_name, const char *oldnew)
 232{
 233        int len;
 234        const char *name;
 235
 236        if (!orig_name && !isnull)
 237                return find_name(line, NULL, 1, 0);
 238
 239        name = "/dev/null";
 240        len = 9;
 241        if (orig_name) {
 242                name = orig_name;
 243                len = strlen(name);
 244                if (isnull)
 245                        die("git-apply: bad git-diff - expected /dev/null, got %s on line %d", name, linenr);
 246        }
 247
 248        if (*name == '/')
 249                goto absolute_path;
 250
 251        for (;;) {
 252                char c = *line++;
 253                if (c == '\n')
 254                        break;
 255                if (c != '/')
 256                        continue;
 257absolute_path:
 258                if (memcmp(line, name, len) || line[len] != '\n')
 259                        break;
 260                return orig_name;
 261        }
 262        die("git-apply: bad git-diff - inconsistent %s filename on line %d", oldnew, linenr);
 263        return NULL;
 264}
 265
 266static int gitdiff_oldname(const char *line, struct patch *patch)
 267{
 268        patch->old_name = gitdiff_verify_name(line, patch->is_new, patch->old_name, "old");
 269        return 0;
 270}
 271
 272static int gitdiff_newname(const char *line, struct patch *patch)
 273{
 274        patch->new_name = gitdiff_verify_name(line, patch->is_delete, patch->new_name, "new");
 275        return 0;
 276}
 277
 278static int gitdiff_oldmode(const char *line, struct patch *patch)
 279{
 280        patch->old_mode = strtoul(line, NULL, 8);
 281        return 0;
 282}
 283
 284static int gitdiff_newmode(const char *line, struct patch *patch)
 285{
 286        patch->new_mode = strtoul(line, NULL, 8);
 287        return 0;
 288}
 289
 290static int gitdiff_delete(const char *line, struct patch *patch)
 291{
 292        patch->is_delete = 1;
 293        patch->old_name = patch->def_name;
 294        return gitdiff_oldmode(line, patch);
 295}
 296
 297static int gitdiff_newfile(const char *line, struct patch *patch)
 298{
 299        patch->is_new = 1;
 300        patch->new_name = patch->def_name;
 301        return gitdiff_newmode(line, patch);
 302}
 303
 304static int gitdiff_copysrc(const char *line, struct patch *patch)
 305{
 306        patch->is_copy = 1;
 307        patch->old_name = find_name(line, NULL, 0, 0);
 308        return 0;
 309}
 310
 311static int gitdiff_copydst(const char *line, struct patch *patch)
 312{
 313        patch->is_copy = 1;
 314        patch->new_name = find_name(line, NULL, 0, 0);
 315        return 0;
 316}
 317
 318static int gitdiff_renamesrc(const char *line, struct patch *patch)
 319{
 320        patch->is_rename = 1;
 321        patch->old_name = find_name(line, NULL, 0, 0);
 322        return 0;
 323}
 324
 325static int gitdiff_renamedst(const char *line, struct patch *patch)
 326{
 327        patch->is_rename = 1;
 328        patch->new_name = find_name(line, NULL, 0, 0);
 329        return 0;
 330}
 331
 332static int gitdiff_similarity(const char *line, struct patch *patch)
 333{
 334        if ((patch->score = strtoul(line, NULL, 10)) == ULONG_MAX)
 335                patch->score = 0;
 336        return 0;
 337}
 338
 339static int gitdiff_dissimilarity(const char *line, struct patch *patch)
 340{
 341        if ((patch->score = strtoul(line, NULL, 10)) == ULONG_MAX)
 342                patch->score = 0;
 343        return 0;
 344}
 345
 346/*
 347 * This is normal for a diff that doesn't change anything: we'll fall through
 348 * into the next diff. Tell the parser to break out.
 349 */
 350static int gitdiff_unrecognized(const char *line, struct patch *patch)
 351{
 352        return -1;
 353}
 354
 355static char *git_header_name(char *line)
 356{
 357        int len;
 358        char *name, *second;
 359
 360        /*
 361         * Find the first '/'
 362         */
 363        name = line;
 364        for (;;) {
 365                char c = *name++;
 366                if (c == '\n')
 367                        return NULL;
 368                if (c == '/')
 369                        break;
 370        }
 371
 372        /*
 373         * We don't accept absolute paths (/dev/null) as possibly valid
 374         */
 375        if (name == line+1)
 376                return NULL;
 377
 378        /*
 379         * Accept a name only if it shows up twice, exactly the same
 380         * form.
 381         */
 382        for (len = 0 ; ; len++) {
 383                char c = name[len];
 384
 385                switch (c) {
 386                default:
 387                        continue;
 388                case '\n':
 389                        break;
 390                case '\t': case ' ':
 391                        second = name+len;
 392                        for (;;) {
 393                                char c = *second++;
 394                                if (c == '\n')
 395                                        return NULL;
 396                                if (c == '/')
 397                                        break;
 398                        }
 399                        if (second[len] == '\n' && !memcmp(name, second, len)) {
 400                                char *ret = xmalloc(len + 1);
 401                                memcpy(ret, name, len);
 402                                ret[len] = 0;
 403                                return ret;
 404                        }
 405                }
 406        }
 407        return NULL;
 408}
 409
 410/* Verify that we recognize the lines following a git header */
 411static int parse_git_header(char *line, int len, unsigned int size, struct patch *patch)
 412{
 413        unsigned long offset;
 414
 415        /* A git diff has explicit new/delete information, so we don't guess */
 416        patch->is_new = 0;
 417        patch->is_delete = 0;
 418
 419        /*
 420         * Some things may not have the old name in the
 421         * rest of the headers anywhere (pure mode changes,
 422         * or removing or adding empty files), so we get
 423         * the default name from the header.
 424         */
 425        patch->def_name = git_header_name(line + strlen("diff --git "));
 426
 427        line += len;
 428        size -= len;
 429        linenr++;
 430        for (offset = len ; size > 0 ; offset += len, size -= len, line += len, linenr++) {
 431                static const struct opentry {
 432                        const char *str;
 433                        int (*fn)(const char *, struct patch *);
 434                } optable[] = {
 435                        { "@@ -", gitdiff_hdrend },
 436                        { "--- ", gitdiff_oldname },
 437                        { "+++ ", gitdiff_newname },
 438                        { "old mode ", gitdiff_oldmode },
 439                        { "new mode ", gitdiff_newmode },
 440                        { "deleted file mode ", gitdiff_delete },
 441                        { "new file mode ", gitdiff_newfile },
 442                        { "copy from ", gitdiff_copysrc },
 443                        { "copy to ", gitdiff_copydst },
 444                        { "rename old ", gitdiff_renamesrc },
 445                        { "rename new ", gitdiff_renamedst },
 446                        { "rename from ", gitdiff_renamesrc },
 447                        { "rename to ", gitdiff_renamedst },
 448                        { "similarity index ", gitdiff_similarity },
 449                        { "dissimilarity index ", gitdiff_dissimilarity },
 450                        { "", gitdiff_unrecognized },
 451                };
 452                int i;
 453
 454                len = linelen(line, size);
 455                if (!len || line[len-1] != '\n')
 456                        break;
 457                for (i = 0; i < sizeof(optable) / sizeof(optable[0]); i++) {
 458                        const struct opentry *p = optable + i;
 459                        int oplen = strlen(p->str);
 460                        if (len < oplen || memcmp(p->str, line, oplen))
 461                                continue;
 462                        if (p->fn(line + oplen, patch) < 0)
 463                                return offset;
 464                        break;
 465                }
 466        }
 467
 468        return offset;
 469}
 470
 471static int parse_num(const char *line, unsigned long *p)
 472{
 473        char *ptr;
 474
 475        if (!isdigit(*line))
 476                return 0;
 477        *p = strtoul(line, &ptr, 10);
 478        return ptr - line;
 479}
 480
 481static int parse_range(const char *line, int len, int offset, const char *expect,
 482                        unsigned long *p1, unsigned long *p2)
 483{
 484        int digits, ex;
 485
 486        if (offset < 0 || offset >= len)
 487                return -1;
 488        line += offset;
 489        len -= offset;
 490
 491        digits = parse_num(line, p1);
 492        if (!digits)
 493                return -1;
 494
 495        offset += digits;
 496        line += digits;
 497        len -= digits;
 498
 499        *p2 = *p1;
 500        if (*line == ',') {
 501                digits = parse_num(line+1, p2);
 502                if (!digits)
 503                        return -1;
 504
 505                offset += digits+1;
 506                line += digits+1;
 507                len -= digits+1;
 508        }
 509
 510        ex = strlen(expect);
 511        if (ex > len)
 512                return -1;
 513        if (memcmp(line, expect, ex))
 514                return -1;
 515
 516        return offset + ex;
 517}
 518
 519/*
 520 * Parse a unified diff fragment header of the
 521 * form "@@ -a,b +c,d @@"
 522 */
 523static int parse_fragment_header(char *line, int len, struct fragment *fragment)
 524{
 525        int offset;
 526
 527        if (!len || line[len-1] != '\n')
 528                return -1;
 529
 530        /* Figure out the number of lines in a fragment */
 531        offset = parse_range(line, len, 4, " +", &fragment->oldpos, &fragment->oldlines);
 532        offset = parse_range(line, len, offset, " @@", &fragment->newpos, &fragment->newlines);
 533
 534        return offset;
 535}
 536
 537static int find_header(char *line, unsigned long size, int *hdrsize, struct patch *patch)
 538{
 539        unsigned long offset, len;
 540
 541        patch->is_rename = patch->is_copy = 0;
 542        patch->is_new = patch->is_delete = -1;
 543        patch->old_mode = patch->new_mode = 0;
 544        patch->old_name = patch->new_name = NULL;
 545        for (offset = 0; size > 0; offset += len, size -= len, line += len, linenr++) {
 546                unsigned long nextlen;
 547
 548                len = linelen(line, size);
 549                if (!len)
 550                        break;
 551
 552                /* Testing this early allows us to take a few shortcuts.. */
 553                if (len < 6)
 554                        continue;
 555
 556                /*
 557                 * Make sure we don't find any unconnected patch fragmants.
 558                 * That's a sign that we didn't find a header, and that a
 559                 * patch has become corrupted/broken up.
 560                 */
 561                if (!memcmp("@@ -", line, 4)) {
 562                        struct fragment dummy;
 563                        if (parse_fragment_header(line, len, &dummy) < 0)
 564                                continue;
 565                        error("patch fragment without header at line %d: %.*s", linenr, len-1, line);
 566                }
 567
 568                if (size < len + 6)
 569                        break;
 570
 571                /*
 572                 * Git patch? It might not have a real patch, just a rename
 573                 * or mode change, so we handle that specially
 574                 */
 575                if (!memcmp("diff --git ", line, 11)) {
 576                        int git_hdr_len = parse_git_header(line, len, size, patch);
 577                        if (git_hdr_len <= len)
 578                                continue;
 579                        if (!patch->old_name && !patch->new_name) {
 580                                if (!patch->def_name)
 581                                        die("git diff header lacks filename information (line %d)", linenr);
 582                                patch->old_name = patch->new_name = patch->def_name;
 583                        }
 584                        *hdrsize = git_hdr_len;
 585                        return offset;
 586                }
 587
 588                /** --- followed by +++ ? */
 589                if (memcmp("--- ", line,  4) || memcmp("+++ ", line + len, 4))
 590                        continue;
 591
 592                /*
 593                 * We only accept unified patches, so we want it to
 594                 * at least have "@@ -a,b +c,d @@\n", which is 14 chars
 595                 * minimum
 596                 */
 597                nextlen = linelen(line + len, size - len);
 598                if (size < nextlen + 14 || memcmp("@@ -", line + len + nextlen, 4))
 599                        continue;
 600
 601                /* Ok, we'll consider it a patch */
 602                parse_traditional_patch(line, line+len, patch);
 603                *hdrsize = len + nextlen;
 604                linenr += 2;
 605                return offset;
 606        }
 607        return -1;
 608}
 609
 610/*
 611 * Parse a unified diff. Note that this really needs
 612 * to parse each fragment separately, since the only
 613 * way to know the difference between a "---" that is
 614 * part of a patch, and a "---" that starts the next
 615 * patch is to look at the line counts..
 616 */
 617static int parse_fragment(char *line, unsigned long size, struct patch *patch, struct fragment *fragment)
 618{
 619        int added, deleted;
 620        int len = linelen(line, size), offset;
 621        unsigned long oldlines, newlines;
 622
 623        offset = parse_fragment_header(line, len, fragment);
 624        if (offset < 0)
 625                return -1;
 626        oldlines = fragment->oldlines;
 627        newlines = fragment->newlines;
 628
 629        if (patch->is_new < 0) {
 630                patch->is_new =  !oldlines;
 631                if (!oldlines)
 632                        patch->old_name = NULL;
 633        }
 634        if (patch->is_delete < 0) {
 635                patch->is_delete = !newlines;
 636                if (!newlines)
 637                        patch->new_name = NULL;
 638        }
 639
 640        if (patch->is_new != !oldlines)
 641                return error("new file depends on old contents");
 642        if (patch->is_delete != !newlines) {
 643                if (newlines)
 644                        return error("deleted file still has contents");
 645                fprintf(stderr, "** warning: file %s becomes empty but is not deleted\n", patch->new_name);
 646        }
 647
 648        /* Parse the thing.. */
 649        line += len;
 650        size -= len;
 651        linenr++;
 652        added = deleted = 0;
 653        for (offset = len; size > 0; offset += len, size -= len, line += len, linenr++) {
 654                if (!oldlines && !newlines)
 655                        break;
 656                len = linelen(line, size);
 657                if (!len || line[len-1] != '\n')
 658                        return -1;
 659                switch (*line) {
 660                default:
 661                        return -1;
 662                case ' ':
 663                        oldlines--;
 664                        newlines--;
 665                        break;
 666                case '-':
 667                        deleted++;
 668                        oldlines--;
 669                        break;
 670                case '+':
 671                        added++;
 672                        newlines--;
 673                        break;
 674                /* We allow "\ No newline at end of file" */
 675                case '\\':
 676                        if (len < 12 || memcmp(line, "\\ No newline", 12))
 677                                return -1;
 678                        break;
 679                }
 680        }
 681        patch->lines_added += added;
 682        patch->lines_deleted += deleted;
 683        return offset;
 684}
 685
 686static int parse_single_patch(char *line, unsigned long size, struct patch *patch)
 687{
 688        unsigned long offset = 0;
 689        struct fragment **fragp = &patch->fragments;
 690
 691        while (size > 4 && !memcmp(line, "@@ -", 4)) {
 692                struct fragment *fragment;
 693                int len;
 694
 695                fragment = xmalloc(sizeof(*fragment));
 696                memset(fragment, 0, sizeof(*fragment));
 697                len = parse_fragment(line, size, patch, fragment);
 698                if (len <= 0)
 699                        die("corrupt patch at line %d", linenr);
 700
 701                fragment->patch = line;
 702                fragment->size = len;
 703
 704                *fragp = fragment;
 705                fragp = &fragment->next;
 706
 707                offset += len;
 708                line += len;
 709                size -= len;
 710        }
 711        return offset;
 712}
 713
 714static int parse_chunk(char *buffer, unsigned long size, struct patch *patch)
 715{
 716        int hdrsize, patchsize;
 717        int offset = find_header(buffer, size, &hdrsize, patch);
 718
 719        if (offset < 0)
 720                return offset;
 721
 722        patchsize = parse_single_patch(buffer + offset + hdrsize, size - offset - hdrsize, patch);
 723
 724        return offset + hdrsize + patchsize;
 725}
 726
 727static const char pluses[] = "++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++";
 728static const char minuses[]= "----------------------------------------------------------------------";
 729
 730static void show_stats(struct patch *patch)
 731{
 732        char *name = patch->new_name;
 733        int len, max, add, del, total;
 734
 735        if (!name)
 736                name = patch->old_name;
 737
 738        /*
 739         * "scale" the filename
 740         */
 741        len = strlen(name);
 742        max = max_len;
 743        if (max > 50)
 744                max = 50;
 745        if (len > max)
 746                name += len - max;
 747        len = max;
 748
 749        /*
 750         * scale the add/delete
 751         */
 752        max = max_change;
 753        if (max + len > 70)
 754                max = 70 - len;
 755
 756        add = patch->lines_added;
 757        del = patch->lines_deleted;
 758        total = add + del;
 759
 760        if (max_change > 0) {
 761                total = (total * max + max_change / 2) / max_change;
 762                add = (add * max + max_change / 2) / max_change;
 763                del = total - add;
 764        }
 765        printf(" %-*s |%5d %.*s%.*s\n",
 766                len, name, patch->lines_added + patch->lines_deleted,
 767                add, pluses, del, minuses);
 768}
 769
 770static int read_old_data(struct stat *st, const char *path, void *buf, unsigned long size)
 771{
 772        int fd;
 773        unsigned long got;
 774
 775        switch (st->st_mode & S_IFMT) {
 776        case S_IFLNK:
 777                return readlink(path, buf, size);
 778        case S_IFREG:
 779                fd = open(path, O_RDONLY);
 780                if (fd < 0)
 781                        return error("unable to open %s", path);
 782                got = 0;
 783                for (;;) {
 784                        int ret = read(fd, buf + got, size - got);
 785                        if (ret < 0) {
 786                                if (errno == EAGAIN)
 787                                        continue;
 788                                break;
 789                        }
 790                        if (!ret)
 791                                break;
 792                        got += ret;
 793                }
 794                close(fd);
 795                return got;
 796
 797        default:
 798                return -1;
 799        }
 800}
 801
 802static int find_offset(const char *buf, unsigned long size, const char *fragment, unsigned long fragsize, int line)
 803{
 804        int i;
 805        unsigned long start, backwards, forwards;
 806
 807        if (fragsize > size)
 808                return -1;
 809
 810        start = 0;
 811        if (line > 1) {
 812                unsigned long offset = 0;
 813                i = line-1;
 814                while (offset + fragsize <= size) {
 815                        if (buf[offset++] == '\n') {
 816                                start = offset;
 817                                if (!--i)
 818                                        break;
 819                        }
 820                }
 821        }
 822
 823        /* Exact line number? */
 824        if (!memcmp(buf + start, fragment, fragsize))
 825                return start;
 826
 827        /*
 828         * There's probably some smart way to do this, but I'll leave
 829         * that to the smart and beautiful people. I'm simple and stupid.
 830         */
 831        backwards = start;
 832        forwards = start;
 833        for (i = 0; ; i++) {
 834                unsigned long try;
 835                int n;
 836
 837                /* "backward" */
 838                if (i & 1) {
 839                        if (!backwards) {
 840                                if (forwards + fragsize > size)
 841                                        break;
 842                                continue;
 843                        }
 844                        do {
 845                                --backwards;
 846                        } while (backwards && buf[backwards-1] != '\n');
 847                        try = backwards;
 848                } else {
 849                        while (forwards + fragsize <= size) {
 850                                if (buf[forwards++] == '\n')
 851                                        break;
 852                        }
 853                        try = forwards;
 854                }
 855
 856                if (try + fragsize > size)
 857                        continue;
 858                if (memcmp(buf + try, fragment, fragsize))
 859                        continue;
 860                n = (i >> 1)+1;
 861                if (i & 1)
 862                        n = -n;
 863                return try;
 864        }
 865
 866        /*
 867         * We should start searching forward and backward.
 868         */
 869        return -1;
 870}
 871
 872struct buffer_desc {
 873        char *buffer;
 874        unsigned long size;
 875        unsigned long alloc;
 876};
 877
 878static int apply_one_fragment(struct buffer_desc *desc, struct fragment *frag)
 879{
 880        char *buf = desc->buffer;
 881        const char *patch = frag->patch;
 882        int offset, size = frag->size;
 883        char *old = xmalloc(size);
 884        char *new = xmalloc(size);
 885        int oldsize = 0, newsize = 0;
 886
 887        while (size > 0) {
 888                int len = linelen(patch, size);
 889                int plen;
 890
 891                if (!len)
 892                        break;
 893
 894                /*
 895                 * "plen" is how much of the line we should use for
 896                 * the actual patch data. Normally we just remove the
 897                 * first character on the line, but if the line is
 898                 * followed by "\ No newline", then we also remove the
 899                 * last one (which is the newline, of course).
 900                 */
 901                plen = len-1;
 902                if (len > size && patch[len] == '\\')
 903                        plen--;
 904                switch (*patch) {
 905                case ' ':
 906                case '-':
 907                        memcpy(old + oldsize, patch + 1, plen);
 908                        oldsize += plen;
 909                        if (*patch == '-')
 910                                break;
 911                /* Fall-through for ' ' */
 912                case '+':
 913                        memcpy(new + newsize, patch + 1, plen);
 914                        newsize += plen;
 915                        break;
 916                case '@': case '\\':
 917                        /* Ignore it, we already handled it */
 918                        break;
 919                default:
 920                        return -1;
 921                }
 922                patch += len;
 923                size -= len;
 924        }
 925
 926        offset = find_offset(buf, desc->size, old, oldsize, frag->newpos);
 927        if (offset >= 0) {
 928                int diff = newsize - oldsize;
 929                unsigned long size = desc->size + diff;
 930                unsigned long alloc = desc->alloc;
 931
 932                if (size > alloc) {
 933                        alloc = size + 8192;
 934                        desc->alloc = alloc;
 935                        buf = xrealloc(buf, alloc);
 936                        desc->buffer = buf;
 937                }
 938                desc->size = size;
 939                memmove(buf + offset + newsize, buf + offset + oldsize, size - offset - newsize);
 940                memcpy(buf + offset, new, newsize);
 941                offset = 0;
 942        }
 943
 944        free(old);
 945        free(new);
 946        return offset;
 947}
 948
 949static int apply_fragments(struct buffer_desc *desc, struct patch *patch)
 950{
 951        struct fragment *frag = patch->fragments;
 952
 953        while (frag) {
 954                if (apply_one_fragment(desc, frag) < 0)
 955                        return error("patch failed: %s:%d", patch->old_name, frag->oldpos);
 956                frag = frag->next;
 957        }
 958        return 0;
 959}
 960
 961static int apply_data(struct patch *patch, struct stat *st)
 962{
 963        char *buf;
 964        unsigned long size, alloc;
 965        struct buffer_desc desc;
 966
 967        size = 0;
 968        alloc = 0;
 969        buf = NULL;
 970        if (patch->old_name) {
 971                size = st->st_size;
 972                alloc = size + 8192;
 973                buf = xmalloc(alloc);
 974                if (read_old_data(st, patch->old_name, buf, alloc) != size)
 975                        return error("read of %s failed", patch->old_name);
 976        }
 977
 978        desc.size = size;
 979        desc.alloc = alloc;
 980        desc.buffer = buf;
 981        if (apply_fragments(&desc, patch) < 0)
 982                return -1;
 983        patch->result = desc.buffer;
 984        patch->resultsize = desc.size;
 985
 986        if (patch->is_delete && patch->resultsize)
 987                return error("removal patch leaves file contents");
 988
 989        return 0;
 990}
 991
 992static int check_patch(struct patch *patch)
 993{
 994        struct stat st;
 995        const char *old_name = patch->old_name;
 996        const char *new_name = patch->new_name;
 997
 998        if (old_name) {
 999                int changed;
1000
1001                if (lstat(old_name, &st) < 0)
1002                        return error("%s: %s", old_name, strerror(errno));
1003                if (check_index) {
1004                        int pos = cache_name_pos(old_name, strlen(old_name));
1005                        if (pos < 0)
1006                                return error("%s: does not exist in index", old_name);
1007                        changed = ce_match_stat(active_cache[pos], &st);
1008                        if (changed)
1009                                return error("%s: does not match index", old_name);
1010                }
1011                if (patch->is_new < 0)
1012                        patch->is_new = 0;
1013                st.st_mode = ntohl(create_ce_mode(st.st_mode));
1014                if (!patch->old_mode)
1015                        patch->old_mode = st.st_mode;
1016                if ((st.st_mode ^ patch->old_mode) & S_IFMT)
1017                        return error("%s: wrong type", old_name);
1018                if (st.st_mode != patch->old_mode)
1019                        fprintf(stderr, "warning: %s has type %o, expected %o\n",
1020                                old_name, st.st_mode, patch->old_mode);
1021        }
1022
1023        if (new_name && (patch->is_new | patch->is_rename | patch->is_copy)) {
1024                if (check_index && cache_name_pos(new_name, strlen(new_name)) >= 0)
1025                        return error("%s: already exists in index", new_name);
1026                if (!lstat(new_name, &st))
1027                        return error("%s: already exists in working directory", new_name);
1028                if (errno != ENOENT)
1029                        return error("%s: %s", new_name, strerror(errno));
1030                if (!patch->new_mode)
1031                        patch->new_mode = S_IFREG | 0644;
1032        }
1033
1034        if (new_name && old_name) {
1035                int same = !strcmp(old_name, new_name);
1036                if (!patch->new_mode)
1037                        patch->new_mode = patch->old_mode;
1038                if ((patch->old_mode ^ patch->new_mode) & S_IFMT)
1039                        return error("new mode (%o) of %s does not match old mode (%o)%s%s",
1040                                patch->new_mode, new_name, patch->old_mode,
1041                                same ? "" : " of ", same ? "" : old_name);
1042        }       
1043
1044        if (apply_data(patch, &st) < 0)
1045                return error("%s: patch does not apply", old_name);
1046        return 0;
1047}
1048
1049static int check_patch_list(struct patch *patch)
1050{
1051        int error = 0;
1052
1053        for (;patch ; patch = patch->next)
1054                error |= check_patch(patch);
1055        return error;
1056}
1057
1058static void show_file(int c, unsigned int mode, const char *name)
1059{
1060        printf("%c %o %s\n", c, mode, name);
1061}
1062
1063static void show_file_list(struct patch *patch)
1064{
1065        for (;patch ; patch = patch->next) {
1066                if (patch->is_rename) {
1067                        show_file('-', patch->old_mode, patch->old_name);
1068                        show_file('+', patch->new_mode, patch->new_name);
1069                        continue;
1070                }
1071                if (patch->is_copy || patch->is_new) {
1072                        show_file('+', patch->new_mode, patch->new_name);
1073                        continue;
1074                }
1075                if (patch->is_delete) {
1076                        show_file('-', patch->old_mode, patch->old_name);
1077                        continue;
1078                }
1079                if (patch->old_mode && patch->new_mode && patch->old_mode != patch->new_mode) {
1080                        printf("M %o:%o %s\n", patch->old_mode, patch->new_mode, patch->old_name);
1081                        continue;
1082                }
1083                printf("M %o %s\n", patch->old_mode, patch->old_name);
1084        }
1085}
1086
1087static void stat_patch_list(struct patch *patch)
1088{
1089        int files, adds, dels;
1090
1091        for (files = adds = dels = 0 ; patch ; patch = patch->next) {
1092                files++;
1093                adds += patch->lines_added;
1094                dels += patch->lines_deleted;
1095                show_stats(patch);
1096        }
1097
1098        printf(" %d files changed, %d insertions(+), %d deletions(-)\n", files, adds, dels);
1099}
1100
1101static void show_file_mode_name(const char *newdelete, unsigned int mode, const char *name)
1102{
1103        if (mode)
1104                printf(" %s mode %06o %s\n", newdelete, mode, name);
1105        else
1106                printf(" %s %s\n", newdelete, name);
1107}
1108
1109static void show_mode_change(struct patch *p, int show_name)
1110{
1111        if (p->old_mode && p->new_mode && p->old_mode != p->new_mode) {
1112                if (show_name)
1113                        printf(" mode change %06o => %06o %s\n",
1114                               p->old_mode, p->new_mode, p->new_name);
1115                else
1116                        printf(" mode change %06o => %06o\n",
1117                               p->old_mode, p->new_mode);
1118        }
1119}
1120
1121static void show_rename_copy(struct patch *p)
1122{
1123        const char *renamecopy = p->is_rename ? "rename" : "copy";
1124        const char *old, *new;
1125
1126        /* Find common prefix */
1127        old = p->old_name;
1128        new = p->new_name;
1129        while (1) {
1130                const char *slash_old, *slash_new;
1131                slash_old = strchr(old, '/');
1132                slash_new = strchr(new, '/');
1133                if (!slash_old ||
1134                    !slash_new ||
1135                    slash_old - old != slash_new - new ||
1136                    memcmp(old, new, slash_new - new))
1137                        break;
1138                old = slash_old + 1;
1139                new = slash_new + 1;
1140        }
1141        /* p->old_name thru old is the common prefix, and old and new
1142         * through the end of names are renames
1143         */
1144        if (old != p->old_name)
1145                printf(" %s %.*s{%s => %s} (%d%%)\n", renamecopy,
1146                       old - p->old_name, p->old_name,
1147                       old, new, p->score);
1148        else
1149                printf(" %s %s => %s (%d%%)\n", renamecopy,
1150                       p->old_name, p->new_name, p->score);
1151        show_mode_change(p, 0);
1152}
1153
1154static void summary_patch_list(struct patch *patch)
1155{
1156        struct patch *p;
1157
1158        for (p = patch; p; p = p->next) {
1159                if (p->is_new)
1160                        show_file_mode_name("create", p->new_mode, p->new_name);
1161                else if (p->is_delete)
1162                        show_file_mode_name("delete", p->old_mode, p->old_name);
1163                else {
1164                        if (p->is_rename || p->is_copy)
1165                                show_rename_copy(p);
1166                        else {
1167                                if (p->score) {
1168                                        printf(" rewrite %s (%d%%)\n",
1169                                               p->new_name, p->score);
1170                                        show_mode_change(p, 0);
1171                                }
1172                                else
1173                                        show_mode_change(p, 1);
1174                        }
1175                }
1176        }
1177}
1178
1179static void patch_stats(struct patch *patch)
1180{
1181        int lines = patch->lines_added + patch->lines_deleted;
1182
1183        if (lines > max_change)
1184                max_change = lines;
1185        if (patch->old_name) {
1186                int len = strlen(patch->old_name);
1187                if (len > max_len)
1188                        max_len = len;
1189        }
1190        if (patch->new_name) {
1191                int len = strlen(patch->new_name);
1192                if (len > max_len)
1193                        max_len = len;
1194        }
1195}
1196
1197static void remove_file(struct patch *patch)
1198{
1199        if (write_index) {
1200                if (remove_file_from_cache(patch->old_name) < 0)
1201                        die("unable to remove %s from index", patch->old_name);
1202        }
1203        unlink(patch->old_name);
1204}
1205
1206static void add_index_file(const char *path, unsigned mode, void *buf, unsigned long size)
1207{
1208        struct stat st;
1209        struct cache_entry *ce;
1210        int namelen = strlen(path);
1211        unsigned ce_size = cache_entry_size(namelen);
1212
1213        if (!write_index)
1214                return;
1215
1216        ce = xmalloc(ce_size);
1217        memset(ce, 0, ce_size);
1218        memcpy(ce->name, path, namelen);
1219        ce->ce_mode = create_ce_mode(mode);
1220        ce->ce_flags = htons(namelen);
1221        if (lstat(path, &st) < 0)
1222                die("unable to stat newly created file %s", path);
1223        fill_stat_cache_info(ce, &st);
1224        if (write_sha1_file(buf, size, "blob", ce->sha1) < 0)
1225                die("unable to create backing store for newly created file %s", path);
1226        if (add_cache_entry(ce, ADD_CACHE_OK_TO_ADD) < 0)
1227                die("unable to add cache entry for %s", path);
1228}
1229
1230static void create_subdirectories(const char *path)
1231{
1232        int len = strlen(path);
1233        char *buf = xmalloc(len + 1);
1234        const char *slash = path;
1235
1236        while ((slash = strchr(slash+1, '/')) != NULL) {
1237                len = slash - path;
1238                memcpy(buf, path, len);
1239                buf[len] = 0;
1240                if (mkdir(buf, 0755) < 0) {
1241                        if (errno != EEXIST)
1242                                break;
1243                }
1244        }
1245        free(buf);
1246}
1247
1248/*
1249 * We optimistically assume that the directories exist,
1250 * which is true 99% of the time anyway. If they don't,
1251 * we create them and try again.
1252 */
1253static int create_regular_file(const char *path, unsigned int mode)
1254{
1255        int ret = open(path, O_WRONLY | O_CREAT | O_TRUNC, mode);
1256
1257        if (ret < 0 && errno == ENOENT) {
1258                create_subdirectories(path);
1259                ret = open(path, O_WRONLY | O_CREAT | O_TRUNC, mode);
1260        }
1261        return ret;
1262}
1263
1264static int create_symlink(const char *buf, const char *path)
1265{
1266        int ret = symlink(buf, path);
1267
1268        if (ret < 0 && errno == ENOENT) {
1269                create_subdirectories(path);
1270                ret = symlink(buf, path);
1271        }
1272        return ret;
1273}
1274
1275static void create_file(struct patch *patch)
1276{
1277        const char *path = patch->new_name;
1278        unsigned mode = patch->new_mode;
1279        unsigned long size = patch->resultsize;
1280        char *buf = patch->result;
1281
1282        if (!mode)
1283                mode = S_IFREG | 0644;
1284        if (S_ISREG(mode)) {
1285                int fd;
1286                mode = (mode & 0100) ? 0777 : 0666;
1287                fd = create_regular_file(path, mode);
1288                if (fd < 0)
1289                        die("unable to create file %s (%s)", path, strerror(errno));
1290                if (write(fd, buf, size) != size)
1291                        die("unable to write file %s", path);
1292                close(fd);
1293                add_index_file(path, mode, buf, size);
1294                return;
1295        }
1296        if (S_ISLNK(mode)) {
1297                if (size && buf[size-1] == '\n')
1298                        size--;
1299                buf[size] = 0;
1300                if (create_symlink(buf, path) < 0)
1301                        die("unable to write symlink %s", path);
1302                add_index_file(path, mode, buf, size);
1303                return;
1304        }
1305        die("unable to write file mode %o", mode);
1306}
1307
1308static void write_out_one_result(struct patch *patch)
1309{
1310        if (patch->is_delete > 0) {
1311                remove_file(patch);
1312                return;
1313        }
1314        if (patch->is_new > 0 || patch->is_copy) {
1315                create_file(patch);
1316                return;
1317        }
1318        /*
1319         * Rename or modification boils down to the same
1320         * thing: remove the old, write the new
1321         */
1322        remove_file(patch);
1323        create_file(patch);
1324}
1325
1326static void write_out_results(struct patch *list)
1327{
1328        if (!list)
1329                die("No changes");
1330
1331        while (list) {
1332                write_out_one_result(list);
1333                list = list->next;
1334        }
1335}
1336
1337static struct cache_file cache_file;
1338
1339static int apply_patch(int fd)
1340{
1341        int newfd;
1342        unsigned long offset, size;
1343        char *buffer = read_patch_file(fd, &size);
1344        struct patch *list = NULL, **listp = &list;
1345
1346        if (!buffer)
1347                return -1;
1348        offset = 0;
1349        while (size > 0) {
1350                struct patch *patch;
1351                int nr;
1352
1353                patch = xmalloc(sizeof(*patch));
1354                memset(patch, 0, sizeof(*patch));
1355                nr = parse_chunk(buffer + offset, size, patch);
1356                if (nr < 0)
1357                        break;
1358                patch_stats(patch);
1359                *listp = patch;
1360                listp = &patch->next;
1361                offset += nr;
1362                size -= nr;
1363        }
1364
1365        newfd = -1;
1366        write_index = check_index && apply;
1367        if (write_index)
1368                newfd = hold_index_file_for_update(&cache_file, get_index_file());
1369        if (check_index) {
1370                if (read_cache() < 0)
1371                        die("unable to read index file");
1372        }
1373
1374        if ((check || apply) && check_patch_list(list) < 0)
1375                exit(1);
1376
1377        if (apply)
1378                write_out_results(list);
1379
1380        if (write_index) {
1381                if (write_cache(newfd, active_cache, active_nr) ||
1382                    commit_index_file(&cache_file))
1383                        die("Unable to write new cachefile");
1384        }
1385
1386        if (show_files)
1387                show_file_list(list);
1388
1389        if (diffstat)
1390                stat_patch_list(list);
1391
1392        if (summary)
1393                summary_patch_list(list);
1394
1395        free(buffer);
1396        return 0;
1397}
1398
1399int main(int argc, char **argv)
1400{
1401        int i;
1402        int read_stdin = 1;
1403
1404        for (i = 1; i < argc; i++) {
1405                const char *arg = argv[i];
1406                int fd;
1407
1408                if (!strcmp(arg, "-")) {
1409                        apply_patch(0);
1410                        read_stdin = 0;
1411                        continue;
1412                }
1413                if (!strcmp(arg, "--no-merge")) {
1414                        merge_patch = 0;
1415                        continue;
1416                }
1417                if (!strcmp(arg, "--stat")) {
1418                        apply = 0;
1419                        diffstat = 1;
1420                        continue;
1421                }
1422                if (!strcmp(arg, "--summary")) {
1423                        apply = 0;
1424                        summary = 1;
1425                        continue;
1426                }
1427                if (!strcmp(arg, "--check")) {
1428                        apply = 0;
1429                        check = 1;
1430                        continue;
1431                }
1432                if (!strcmp(arg, "--index")) {
1433                        check_index = 1;
1434                        continue;
1435                }
1436                if (!strcmp(arg, "--apply")) {
1437                        apply = 1;
1438                        continue;
1439                }
1440                if (!strcmp(arg, "--show-files")) {
1441                        show_files = 1;
1442                        continue;
1443                }
1444                fd = open(arg, O_RDONLY);
1445                if (fd < 0)
1446                        usage(apply_usage);
1447                read_stdin = 0;
1448                apply_patch(fd);
1449                close(fd);
1450        }
1451        if (read_stdin)
1452                apply_patch(0);
1453        return 0;
1454}